Nonvolatile semiconductor memory devices represent a multibillion-dollar market. The nonvolatile semiconductor memory technology best known in the prior art operates by injecting holes or electrons into a thin film serving as the gate dielectric of a field effect transistor, thereby shifting the turn-on threshold voltage negatively or positively. Such memories include flash and nonvolatile memories based on silicon nitride thin films. Electrons or holes are injected into a thin film by applying a voltage significantly larger than the read operating voltage. Such memories are known to exhibit excellent retention characteristics, but have marginal endurance properties, slow write times, and high power consumption during write cycles. What is desired, therefore, is a nonvolatile semiconductor memory device that exhibits the desirable characteristics of a flash memory such as small cell size and excellent data retention, but without the undesirable properties of low endurance, slow write times, and high power consumption.